html body{
    height: 100%;
}
body{
    font-size: 16px;
    /*background-color:#ffff01;*/
    background-image: url("../img/beijing.png");
    background-position: center top;
    background-size: cover;
    background-repeat: no-repeat;
}

#b1 img{
    width: 6.33rem;
    height: 6.72rem;
    margin-top: 1.74rem;
}
.btn{
    width: 4.82rem;
    height: .8rem;
    border-radius: 10px;
    border: 6px solid #690eff;
    background-color: #ffd201;
}
.btn{
    position: relative;
}
.button{
    display: inline-block;
    position: absolute;
    top: -.22rem;
    left: -.22rem;
    background-color: white;
}
/*.button>img{*/
    /*width: 1.85rem;*/
    /*height: .43rem;*/
/*}*/